Apparatus for dehydrating petroleum products in situ in tank storage



E. P. BAKER APPARATUS FOR DEHYDRATING PETROLEUM PRODUCTS IN SITU IN TANKSTORAGE Feb. 1, 1949.

3 Sheets-Sheet 1 Filed July 12, 1945 m r W m M J 2 M ATTORNEY Feb. 1,1949. 2,460,271

E. .BAKER APPARATUS FOR DEHYDRATING PETROLEUM PRODUCTS IN SITU IN TANKSTORAGE Filed July 12, 1945 s Sheets-Sheet 2 INVENTOR Edward F fia/ferHTTORNEY APPARATUS FOR DEHYDRATING PETROLEUM Feb.1, 1949. 5P. BAKER.2,460,271-

. PRODUCTS IN S'ITU IN TANK STORAGE Filed July 12, 1945 3 S heetsSheet 5INVENTVOR Edward Ziiaifer HTTORNEY Patented Feb. 1, 1949 APPARATUS FORDEHYDRATING PETRO- LEUM PRODUCTS IN SI'EU IN TANK STOR- AGE Edward P.Baker, New York, N. Y.

Application July 12, 1945, Serial No. 604,570

9 Claims.

This invention relates to storage tanks for storing petroleum productsand other liquids which in their intended uses must be substantiallyfree from water but tend to become contaminated with small butnevertheless objectionable amounts of water when stored in tanks oflarge volume. The invention has more particular application to suchtanks set in the open and constructed of metal sheets or plates, andwhich are provided with a metal roof structure for preventing rain orsnow from entering the tank.

In storing petroleum products in such tanks a certain amount ofcirculation of atmospheric air Within the space between the stored bodyof oil or other liquid and the roof is usually unavoidable. Unclercertain conditions, condensation of water from the vapor within suchspace will occur on the inner surfaces of the roof structure and on thewalls and other surfaces of the tank exposed to the atmosphere existingin such space and this water may drop from the structure or run down thesurfaces into the liquid petroleum product and become entrained therein.The condensation may occur with changes in the weather producing asaturated condition of the water vapor in the air space above the liquidin the tank. For example, air which has entered the tank during a warmspell, replacing the contents of the tank or a portion thereof withdrawnfor use, may contain a relatively large amount of moisture. Upon a fallof temperature of the'atmospheric air the roof and the Walls of thetank, particularly those constructed with metal, rapidly reduce intemperature and the vapor in contact therewith may be reduced to the dewpoint, so that condensation of water from the vapor readily takes placeupon the roof and walls. Even in tanks which are filled to the normallevel with the petroleum product the air in the space above the liquidlevel may contain or take up suflicient moisture in the normal movementof air to and from the space within the tank to produce condensation onthe inner surfaces of the side Walls and roof when these surfaces withwhich it is in Contact become cooled. This condensation of water givesrise to the formation of droplets which will eventually grow in size orunite to form larger drops until their Weight is sufiicient to causethem to run down the walls of the tank or to drop from an under surfaceor a projecting portion of the wall or roof structure into the e'troleumproduct within the tank.

Heretofore it has been regarded as practically unavoidable thatpetroleum products would pick up water in the manner above described instorage, and it has been a more or less general practice in storing andhandling heavier petroleum oils such as lubricating oils, fuel oils andthe like, to heat the oil by means of steam coils immersed in the oilbody in the tank. Usually this heating treatment will occur when it isdesired to increase the fluidity of the oil preparatory to pumping itinto tankers or tank cars for transport, but frequently such treatmentmust be carried on for a prolonged period before the moisture example,under winter conditions when the temperature outside the tank and of theexposed metal surfaces of the roof and adjacent side wall portions willbe relatively low as compared with that required to drive the entrainedmixture from the oil body. Under these conditions, the Water vapordriven into the free space above the oil body has a great tendency tocondense on the cooler surfaces of the roof and adjacent wall portionsof the tank and to drip or run back into the oil body.

It is an object of the invention to prevent the condensate of watervapors Y which ordinarily forms in tanks in which petroleum products arestored from running down the surfaces thereof into or falling into thepetroleum product within the tank from the roof or other parts of thetank structure.

It is another object of the invention to provide means for promoting andcontrolling the condensation of water vapors present in the ambientatmosphere within the tank and to collect the condensate and conduct itaway to a place of disposal without remingling with the petrolelllllproduct.

An additional object of the invention is to provide means forcontrolling collection and disposal of the moisture driven off from apetroleum product during heating so as to prevent its reentrainment inthe product.

A further object is to provide an improved and relatively inexpensivemethod of dehydrating petroleum products and other liquid that tend totake up or become contaminated with moisture in handling and storage.

In order to accomplish the above and other objects it is proposedaccording to the invention to provide means for inducing condensationwithin the vapor laden space above the petroleum product within the tankand beneath the roof' tmC u e thereof. This means may comprise aplurality of members providing a condensation inducing structureenveloped by the water vapor within said space and extending generallyhorizontally, substantially completely across the internal cross-sectionof the tank. These members and this structure are made of heatconducting material and this structure is arranged in heat conductingrelation to the tank structure or to other means for conducting heatfrom said members in order that these members shall be maintained at atemperature which will induce condensation on the surfaces thereof,including the under surface thereof, when the condition of the vapor insaid space is such that condensation occurs on the roof and wallstructure of the tank.

As tanks for the storage of petroleum products ordinarily areconstructed with iron or steel plates for the tank walls and roof andwtih steel structural members for support thereof, in its preferredembodiment the invention utilizes as the condensation-inducing membersmetal sheets preferably of corrosion resisting material. These sheetsare supported by the tank structure, and for the most part by the roofstructure, by means of hangers or supports of heat conducting material,such as iron or steel rods or straps. These hangers or supports arefastened to the tank or to the roof structure as well as to the metalsheets of the condensation-inducing structure in heat conductingcontact. As the condensation within a tank of the type to which theinvention relates occurs for the most part when the atmospheric air isat a temperature low enough to reduce the temperature of the roof andadjacent wall portions of the tank to or below the dew point of thevapor within the space above the liquid within the tank, the provisionof heat conducting connections and supports between thecondensationinducing structure and the tank structure ordinarily issufficient also to reduce the temperature of this structure at least tothe dew point and thus produce the condensation thereon. Within thescope of the invention any suitable means may be used for securing therequisite reduced temperature of the sheets or other members pro vidingthe condensing surfaces.

By arranging this condensation-inducing structure so as to extendsubstantially completely across the tank, condensation which is formedon the under side of roof of the tank or on its supporting structuralmembers and which drips therefrom is intercepted. Thiscondensation-inducing structure may be so formed and arranged in thespace above the liquid level in the tank that the water thus drippingthereon may run downwardly along its upper surface, for example, towardthe wall of the tank, and be collected or conducted to a place ofdisposal.

It is a further important feature of the invention that the undersurfaces of the condensation inducing structure, or appropriatelyassociated sections thereof, are inclined to the horizontal sufiiicentlyto cause any condensate formed thereon, to run sufficiently freely downthis under surface under the action of gravity to insure that suchcondensate will not in its travel form into droplets of sufficient sizeto overcome the surface tension effect and drop off into the oil bodybeneath. The condensation-inducing structure may be made up of aplurality of sections which are of lengths, not exceeding apredetermined maximum length in the direction of the inclination of theunder surface thereof, such that the moisture film and drops whichcollect on the under surface will flow along said under surface whileclinging thereto until the edge of said section is reached beforedropping therefrom. Upon reaching this lower edge or other meansproviding a drip element adjacent the lower end of the predeterminedlength along which a drop travels down this inclined under surfacebefore dropping from said surface, the drop together with any waterrunning over said lower edge from the upper surface of said member willdrip from said lower edge or from said drip element.

In order to prevent the water thus condensing upon the under surface ofthese sections and dripping from the lower edges thereof from fallinginto the petroleum product within the tank, the sections are arranged inoverlapping relation with the lower edge of one section overlapping uponbut spaced somewhat above the upper edge of the subjacent section. Thewater dripping from the lower edge of the superjacent section thus mayfall upon the upper surface of the subjacent section and may run downthis upper surface of this section toward the lower edge of thesubjacent section. The water running upon the upper surfaces of saidsections and carried successively thereover ultimately to the lower edgeof the lowermost section of the condensation-induc ing and conductingstructure may drip from said lowermost edge into a collector, such as agutter arranged therebeneath.

This arrangement of the sections in overlapping relation and with thelower edge of each section spaced above the upper edge of the subjacentsection makes possible not only a simple construction, as will beapparent hereafter, but also provides space between the sections for thevapor within the vapor laden space to circulate between and to envelopethe sections so as to come into contact with all of the exposed surfacesthereof. The condensation-inducing and conducting structure thusenveloped by the vapor, therefore, may be in contact with the vapor bothat the under surface to which the condensate clings by surface tensionand at the upper surface upon which the water dropping thereon from theroof structure, or condensed directly thereon from the vapor in contacttherewith, may run toward the lowermost edge of saidcondensationinducing and conducting structure. The spacing of thesections one above the other at the overlapping portions also must besufiicient to permit the drops which run on the under surfaces to reachthe lower edge of the section of predetermined maximum length withouttouching the subl'acent overlapped sections. If the drops were thus totouch said section the surface tension would cause them to pass aroundthe edge to the under side of said suhjacent section Where by unitingwith other drops they might increase their weight sufficiently to causethem to drop from said under surface into the petroleum product in thetank before running to the lower edge of the subjacent section.

A corollary feature of the invention is related to the feature abovedescribed of inducing formation of drops of such size as to run upon theunder surfaces of the sections without dropping therefrom beforereaching the lower edges thcreof. In accordance with this corollaryfeature the under surfaces of said sections are formed with ridges,preferably ridges providing a rounded surface projecting downwardlytherefrom, these ridges being arranged so that their lengths extend inthe direction of the inclination of the under surfaces. The ridgespreferably also ex-- tend parallel to each other and are of such sizeand spacing in consideration of the inclination of the length of theridge to the horizontal that moisture condensed thereon will becomeunited into drops clinging only by surface tension to the under surfacesof these ridges and will run along the ridges toward the lower end ofthe section without dropping therefrom. Upon reaching the lower ends ofthe ridges the drops will drip therefrom onto the upper end portion ofthe section beneath.

Such ridged sections conveniently may be provided by corrugated sheetmetal, preferably of the type providing rounded corrugations, thevalleys between the ridges at the upperside of the sheet serving toconduct toward the lower edge of the sheet the water drop-pingthereon'from the roof structure or condensed on the upper surface or"the corrugated sheet. Such rounded ridges or corrugations also limit theamount of the condensation which will become united into drops becauseof the limited spacing between the ridges or corrugations. Theyfurthermore prevent the water which is formed by the uniting of dropletsand drops from becoming a stream running rapidly and somewhatirregularly over the surface and sometimes running into adjacent streamsin the manner in which this may occur on a flat surface. The watertherefore drips from the lower end of each memher and from the lowermostmember in a distributed manner.

In another aspect the invention provides a method for dehydratingpetroleum products in storage. This process utilizes the step heretoforepracticed of heating the petroleum, for example, by means of steam pipesplaced within the v body of the petroleum product within the tank.According to the process of the invention, however, this heating stepmay be carried on for a sufficient length of time to remove all or thedesired amount of the moisture which may have become entrained in thepetroleum product due to any of the conditions which have been describedabove. The heating may be carried on continuously for the requisiteperiod to effect such removal and the process of the invention providesfor continuous condensation and removal of the moisture thus driven offfrom the petroleum product and which passes up through the body of theproduct within the tank to the surface thereof to escape into the spacebetween the surface and the roof of the tank.

The condensation structure above described positioned in this space maybe maintained by any suitable means at a temperature which will serve tocondense on said structure the moisture thus driven into and fillingthis space by heating of the product in the tank. This structure alsoserves to prevent return, as by dropping from the rent structure andfrom the condensing structure itself, of the condensate which is formedthereon and upon the roof structure. The process of the invention,therefore, provides for dehydration of the liquid petroleum product bysupplementing the heating step by the further steps of condensing themoisture driven on by heating and of conducting the condensate away fromthe vapor laden space to a place of disposal under the action of gravitybut also under the control which utilizes surface tension formaintaining the condensate clinging to the under surface of thecondensing structure as it runs on said under surface. The dehydrationof the petroleum product While it is in storage in the tank, therefore,may be accomplished without the necessity of removal of the product bypumping to special dehydrating apparatus. The process, therefore, may becarried out at any convenient time during the period of storagepreparatory to removal of the product from the tank.

Other objects and features of the invention will be understood from thedescription to follow of the drawings in which Fig. 1 is a plan viewtaken on line l-l of Fig. 2 showing an embodiment of the invention whichutilizes a plurality annular radially overlapping sections made up ofcorrugated sheet metal to provide the condensation-inducing andconducting structure;

Fig. 2 is a vertical section on line 2-2 of Fig.1;

Fig. 3 is a vertical section on line 3-3 of Fig. 1, showing a detail ofthe means of supporting the corrugated sheets;

Fig. 4 is a vertical section on line 4-4. of Fig. 3;

Fig. 5 is a horizontal section taken on line 5-5 of Fig. 3;

Fig. 6 is a horizontal section taken on line 66 of Fig. 2 showing meansfor supporting the structure on the central column of the tank;

Fig. 7 is a plan view taken on line 1-'l of Fig. 8 showing a modifiedembodiment of the invention;

Fig. 8 is a vertical section taken on line 8-8 of Fig. 7;

Fig. 9 is a section taken on line 9-4] of Fig. '7 and showing a detailof the support for the members upon a center line of the tank;

Fig. 10 is a section on line Ii -ls of Fig. '7; and

Fig, 11 is a plan view of another modification of the structure of theinvention.

In Figs. 1 and 2 the condensation-inducing and conducting structure isprovided by sheets i, 2 and 3 of corrugated sheet steel which preferablyis galvanized in order to resist rusting. These sheets are arranged inoverlapping arrangement as may be seen in Fig. 2 and are inclined to thehorizontal so that condensate falling thereon from the roof will runtoward the lower edge of each sheet. Condensate falling on the uppermostsheet 3 will drip from the lower edge 5 thereof upon the upper surfaceof the middie sheet 2 and will run on its upper surface, together withcondensate falling directly thereon, toward the lower edge I of sheet 2from which it will drip upon the upper surface of sheet I. The waterthus brought together from the sheets 2 and 3 will run upon the uppersurface of sheet i, together with water which may have dropped directlyon sheet l from the roof H or the supporting beams l2 thereof, and willdrip from the lower edge 9 of sheet I. Adjacent the tank wall is agutter I5 is supported to receive the drip from the lower edge of sheetI.

For support of the sheets I, 2 and 3, a channel beam I! may be erectedwithin the tank and supported by suitable means adjacent the tank walland upon a collar 55 supported on the centralsupport l9 commonly used insuch a tank structure for support of the roof beams 42. Hangers 2!,depending from channel l'l adjacent the lower end of each of the sheetsi, 2 and 3 and also adjacent the upper end of the sheet 3, are provided.These hangers are fastened by bolts 22 to the channel beam ll and arealso fastened by bolts 25 to the smaller cross chan nels 2?. These crosschannels are fastened by means of bolts 29 to the sheets l, 2 and 3adds.

cent the lower ends thereof. In the embodiment being described thecorrugations 3| of the sheets i, 2 and 3, extend generally radially inthe direction from the central support I9 toward the wall of the tankand symmetrically with respect to the adjacent radially positionedchannel beams ll, as shown in dotted lines in Fig. l. The assembledsheets i, 2 and 3 form sectors the edges of which are substantially inthe vertical planes of the channel members l'i.

vThese radial edges of the sectors, as will be noted from Fig. 1, outdiagonally across the corrugations of the sheets i, 2 and 3. There isthus formed no continuous straight edge along these radially extendingedges of the sheets and of the sector assembly formed by these sheets I,2 and 3 in their overlapping arrangement. Water. therefore, which asdrops might tend to drip from such a continuous straight edge, byrunning along the inclination of such an edge and uniting with otherdrops until they become heavy enough to fall from such an edge, isprevented from doing so because it may only run to the low point of eachof the corrugations crossed by the diagonally extending edge. Thus, asmay be seen in Fig. 3, any water falling on the upper sides of thesheets i, 2, or 3 in the righthand sector shown in this figure, insteadof dripping from the edge 33 will merely run along this edge until itreaches the next lowest point in the corrugation. Here it may passaround to the under side of the sheet by surface tension and then becarried to the lower edge 5, i or 9 as the case may be, of the sheetfrom which it falls onto the next lower sheet in the series or intogutter l 5. Thus, although the radially extending edges of the sectorsin the embodiment illustrated in Figs. 1 and 2 do not overlap but merelyare in adjacent relation as shown in Fig. 3, there will be no leakage ofwater through the condensation-inducing structure of the invention whichmay fall into the petroleum product stored in the tank.

It will be clear from the details shown in Figs. 3, i and and from therelation of the sheets I. 2 and 3 shown in Fig. 2, that each of saidsheets in the portion where it overlaps the subjacent sheet isvertically spaced from said subjacent sheet. For this purpose spacers3-5, which may be made of pipe of suitable size to fit around bolts 29,are placed between the two overlapping sheets I and 2 for example inFig. 3. These spacers 35 hold the sheets apart when the bolt 29 isinserted through the lower iiange (l? of the channel member 22 and thesheets I and 2 are fastened in place in such spaced relation by means ofthe nut 30 running on the lower end of the bolt 29. The spacing of thesheets i and 2 and of the sheets 2 and 3 provides passages for vaporsdriven ofi from the oil body when it is heated to escape from the spacebeneath the condensate-collecting and conducting structure to the spacebetween the roof structure it and i2 and such condensate-collecting andconducting structure. In this way the vapors evolved from the oil bodynot only are readily contacted with and subjected to the condensingaction of the cooler surfaces of each of the sheets i. 2 into contactwith the surfaces of the roof, which will usually be still colder underweather conditions when the problem of drying petroleum products is mostacute.

In the embodiments illustrated it has been as sumed that the tank wouldhave a diameter of about 35'. Additional annular sections of sheets willbe provided for larger diameter tanks. Having regard to the inclinationof the sheets I, 2

and 3, but are also enabled to come and 3 necessary to produce thedesired movement of the water thereon under the action of gravity, thevertical spacing of the overlapping portions of the sheets may be about2" when utilizing corrugated metal sheets having a depth of corrugationof about -7 Such dimensions are merely indicative and may be varied tosuit practical conditions provided the spacing may be sufiicient forample circulation of the Vapors evolved from the liquid being stored.

To hold the sector assemblies of the sheets I, 2 and 3 in properrelation to each other a strap 40 may be formed with a slight bend toconform to the positions of the two channels 27 of adjacent sectors asshown in Fig. 5. The bolt 25 for fastening the hanger ii to the channel21 may also pass through this strap 49, all of the engaging parts beingfastened together by said bolt and its nut 26. In order to provide arigid connection and to prevent movement of the sectors relative to eachother two bolts 4| and 42 are used to fasten the opposite end of thestrap 40 to the adjacent channel 27. The hanger 2i thus may act tosupport the adjacent ends of both of said channels in two adjacentsectors. As will be seen in Fig. 1, therefore, only one hanger 2| isutilized in the embodiment being described for suspension from each ofthe channels i! which extend radially from the central support.

By means of said bolts 25, M and 42 and the strap 40 as well as thehanger 2| and its fastening bolt 22, good heat conducting contact may besecured between the channels 21 and the supporting radial channels H.These channels I1 may be supported at the ends thereof in good heatconducting contact with the tank structure or, if necessary, byadditional connections between said channels El and the roof structureto insure heat transmission by conduction between the channel I7 and.the wall and roof structure.

The bolts 29 and the spacers 35 serve to hold the sheets I, 2 and 3 ingood heat conducting contact with the supporting channel members 27 sothat the heat may be conducted from the sheets I, 2 and 3 through saidchannels 21 and the hangers 2i to the roof structure. As many bolts andspacers may be provided intermediate the ends of the channels 21 as arerequired to hold the sheets in good contact with said channels and toprevent sagging ofthe sheets in their width. Other expedients may beadopted if required for producing good heat conducting contact, such asshaping the ends of the spacers to conform to the corrugations of thesheets and providing washers for the nuts 30 which also conform to thesecorrugations. Ordinarily the connections between the parts will besuificient to provide for the requisite heat conduction.

The lower end 9 of the sheet I is spaced somewhat from the tank wall soas to permit the water running upon the upper and under surfaces of thesheet I to drip into the gutter i5 mounted on the wall l3 of the tank.As the sheets I, 2 and 3 are of corrugated form, the corrugationsprovide a plurality of valleys for conducting the water freely beneaththe lower flanges of the channels 21. The gutter i5 is madesubstantially watertight to the wall of the tank l3 so as also tocollect condensate which may form on and run down the tank wall. Thisgutter may also be provided with a slope in one direction or the'otheror both directions circumferentially of the tank for conducting thewater to drain pipes l6 which may be placed adjacent the columns M whichare part of the tank construction for stiffening and supporting the tankwall. The pipes l5 may lead the collected water to a suitable place ofdisposal outside of the tank. 1

Adjacent the central supporting column l9 the radially extendingchannels H are supported on a collar 45, which for convenience may beformed in two parts as shown in Fig. 6, extending about the column l5and fastened thereto by suitable means such as tap bolts threaded in thecolumn wall. As shown in Fig. 6 the collar 45 may be insulated from thecolumn !9 by a ring 4? of suitable insulating material inorder toprevent conduction of heat from the column 59 through the channels H tothe roof structure. insulating pads 43 also may be provided at the topoff the column 59 between the beams i2 and said colmm to prevent Or im t.2 99ml. qn 9 hea from the Column d rect y to th ree stru turey s in a nt olu n 9 om he chems I l n f om t e 'Ooi he co umn l3 may h aintained mre ne r y he temp rat re o the petroleum product within the tank and notbecome reduced to the dew point temperature of the vapor in the spaceabove the petroleum product. Condensation on said column itself,therefore, may be prevented or reduced, thus avoiding the necessity ofcollecting of such condensate from the surface of the column 89.

It is to be understood, however, that the provision of insulationbetween the column l3 and the upp rtin in '5 an b en e h ad o th column53 and the roof beam is optional. I; such insulation is omitted thecolumn may act, to some e tent t st. as a c dens n ur a ebecause of heattransfer between the column the root. In such case, the ring 45 may actto catch any condensate formed on the column and direct it to the uppersurfaces of the adjacent sheets 3 6!.

inclination of the sheets to the horizontal must, of course, be suffcient to isure thatthe water condensed 0 the surface will be caused 110down. al ne such su ac ui fi ently r pidly to be carried to the loweredge of each sheet ef it ha formed int dr ps of such size as to overcomethe sur iage tensionieifeot and drop off into the stored liquid- Theminimum angle of inclination of the sheets that may be employed withoutrisk of the undesired dripping of the condensate from the under surfaceof the sheets, will vary with the character of the metal surface andwith the length of the sheet. The requisite inclination for a sheet.of-a given kind, say plain stainless steel, aluminum, ,or ordinarygalvanized iron sheets, for a given length of the sheet may bedetermined by making suitable preliminary tests simulating actualconditions as they will exis in the storage tank. I

As previously stated, it is preferred to use corrugated sheets becausethe corrugation-s serve to direct the condensate to the lower portionsof the corrugations whence they will travel more freely along the sheetsto the lower edge and then fall onto the upper surface of the next lowersheet or into the peripheral trough as the case may be. i 1

It is desirable to maintain the radial inclination of the sheets as lowas is consistent with the proper flow of the condensate along the sheetswithout dripping off since in this way the amount of space taken upvertically in the upper portion of the tank by the condensation-inducingand conducting structure isminimized. By way of example, by usinggalvanized iron or steel having corrugations of standard depth of aboutI have found that if corrugated sheets of 6 in length are disposed at aninclination of about l 2 to the horizontal there will be no substantialdrip-ping of the condensate collecting on the under surface thereofuntil it reaches the lower edge or"- the sheet whereit is intended thatit shall drop off on the next adjacent lower sheet. This inclination wasadopted in anticipation thatthere would be a greater tendency for thecondensate to drip off after the structure has been installed for sometime, due to corrosion eiiects or other influences affecting thesmoothness of the surface of the sheet. 'On new corrugated galvanizedsheet material an inclination to the horizontal of 4 has been foundadequate to insure the desired flow for the full length of sheets 6' inlength.

In Figafl and 8 is shown a modified arrangement of corrugated sheets toprovide the condensation-inducing and conducting structure of theinvention. Ehis modification permits the use for the most part ofrectangular sheets having dimensions in which such sheets are commonlymanufactured. The supports for these sheets may be arranged similarly tothe arrangement shown in Figs 1 to '5. In this embodiment, however, theassembly of the sheets is shown supported directly from the roof beamsof the tanl; without the intervention of an additional supportingmember, such as the channel ll shown in Figs. 2, 3 and 4. In 7 theradially extending broken lines represent the positions or the roofbeams ts the roof structure, one end of each beam resting uponstructural member 51 extending circumfereh tially along the wall of thetank adjacent the top thereof. l'he other end of the beam as wlnlcl'i,-as may be seen above the column I!) maybe of channel section, bears uponthe upper end of the column [9. Aminsulating pad 48 maybe provided toprevent or reduce conduction of heat from the column 38 to the beams{50.

In this embodiment the members 63, E i and 65 are positioned in tierseach consisting of a plurality of rectangular sheets of corrugated sheetsteel arranged in each tier with the lengthwise edges thereof inoverlapping nesting relation as show-n in Fig. 10. Adjacent the lowerend of each tier and extending along the transverse lower edge of eachsheet the channels 27 may be fastenedto the sheets 53, es and 55 in thesame manner as provided in the construction of Figs-1 and 2. Thesectional view shown in Fig. 4 to enlarged scale represents thearrangement of the channels 2-! in relation to the overlapping sheets53, lid and M, 55, in which the spacers '35 and the bolts 29 with theirnuts 3% hold the sheets 6-3, M and 55 in the requisite vertically spacedrelation. The hangers i may be fas toned at their lower ends to thechannels 2'? in the construction shown-in Figs. 1 and 8 by means of thebolts 25 and may be fastened at their upper ends to the supporting roofbeam by means of bolts 22 in the same manner as in Figs. 1 and 2. r

The channel 2? adjacent the lower end of the lowermost member 63 may bepositioned with respect to the lower edge 6-! of said member as so astoextend across the chord of the circular are formed by the edges of thesheet 68 in the assembled structure as shown in Fig. 7'. Whiere thecolumn lipositioned at the wall of the would in-ter-fere with thechanneld i adjacent the lower edge of the sheet 63, this channel 69, asshown in Fig. 7, may be kept back from said lower edge to clear thecolumn M. The sheet or sheets 63 adjacent such column It may be cut toclear said column in order that the water passing over the lower edge 61thereof may fall clear of the column l4 so as to prevent the waterrunning down said column into the petroleum product. The gutter l whichis provided beneath the lower edge 61 of the lowermost sheets may :beformed at the column M to receive the portion of the condensate whichdrips from this portion of the lower edge 61. As in the arrangement ofFigs. 1-5 the water running in the valleys on the upper surfaces of thelowermost sheets 63 when of corrugated form may pass under the lowermostchannel 21 or 69 without obstruction.

Adjacent the diameter of the tank, that is, beneath two oppositelyextending roof beams 60, shown on the vertical center line in Fig. '7, apair of channels 1|, 12 may be arranged to which respectively arefastened by bolts 13 the upper ends of the uppermost tiers of sheets 65.These channel members II and 72, as shown in Fig. 9, may be boltedtogether by bolt 15 passing also through the hanger 16 which is fastenedto the channel beam 60 immediately above by bolt Tl. By means of thebolts 13 and suitable washers, if needed, the sheets 65 may be held ingood heat conducting relation with the channels II and 12 and with thehanger l6 and the roof beams 60. As many bolts 13 as are requisite tohold the sheets 65 in good contact with channels TI, 72 while providingadequate support for said sheets may be used. Depending upon the size ofthe channels H and 12 a greater or less number of the hangers 16 may beused having regard also to the provision of heat conducting membersconnecting to the roof to effect reducextent of thecondensation-inducing structure.

Those hangers 2| which support the members 21, 69 which are adjacent thewall of the tank may be connected to each of the radially extendingbeams 50. The channels 21, 69 in the arrangement shown in Fig. 7 for themost part extend across two of the corrugated sheets 63 transverse-- lyto the corrugations thereof and may be of such section as to supportthese two sheets upon a single hanger 2|, the straps 40, as shown inFigs. 3, 4 and 5, serving in this construction also to join adjacentsections supported by channels 2'! so as to produce a rigid structureand to transfer the load to the hangers 2|. The channels 21 extendingalong the lower edges of sheets 64 and 65- may be of any suitable lengthand may be joined by straps similar to the straps 40.

As in the construction shown in Figs. 1 and 2, the gutter |5 may extendbetween the columns [4 and may be connected to drain pipes l6 adjacentsaid columns for conducting away the condensate in the same manner asdescribed in connection with Fig. 1.

In Fig. 11 another modification of the condensation-inducing andconducting structure of the invention is shown in diagrammatic outline.

ill

Between the central column l9 and the wall of the tank sectors 30 ofsheet metal of appropriate sector size, approximately 90 in the exampleshown, may be supported by hangers 82 which may be fastened to thesupporting beams of the tank in any suitable manner to produce a rigidsupport. As in the embodiments previously described sectors 80 areconstructed with individual sheets or tiers 84, 85, 86, each of whichhas a radial dimension of a predetermined maximum length similar to thelength of the sheets I, 2, 3, 63, 64, 65, so as to prevent waterdropping from the underside thereof before reaching the lower edge 81 ofeach sheet. Each of the sheets 84, 85, 86 is arranged inclineddownwardly to the wall of the tank and with its lower edge inoverlapping relation to the subjacent sheet, so that water dripping fromthelower edges 81 may fall upon the subjacent sheet or tier and becarried over the upper surface thereof to the adjacent sheet or tier. Agutter 89 may be provided to catch the drip from the lowermost edge ofthe sheets adjacent the tank wall, as in the embodiments previouslydescribed.

In the embodiment of Fig. 11, the lateral edges 9|, 93 are shown inoverlapping relation. Means may be provided for vertically spacing thesectors at their overlapping lateral edges, as well as at their loweredges 81 with respect to the upper edges of the subjacent sheets, toprovide for passage of the vapors between the sheets and sectors so thatit may come into contact with both the upper and lower surfaces thereof.The overlapping arrangement of the lateral edges 9|, 93 preventscondensate falling from the roof of the tank from reaching the petroleumproduct in the tank. The arrangement of the sectors and sheets with alledges overlapping and extending substantially completely across thecrosssection of the tank is advantageous where the sheets are smooth,that is not provided with ridges running in the direction of theinclination. The construction shown in Fig. 11 also may be advantageouswhere it is inconvenient to support corrugated sheets in the mannerdescribed in the previous embodiments or where because of availabilityof materials or for other reasons plain sheets, that is, those withoutcorrugations or other fabricated form, may be used to greater advantage.

By providing the usual heating coils placed within the body of thepetroleum product within the tank and supplying them with a heatingmedium such as steam, dehydration of the product may be accomplishedwhile the product remains in the tank. Vapor of Water driven oil fromthe product by such heating into the space above the product and beneaththe roof structure may be condensed not merely on the roof structure butupon the sheets 2, 3, 63, 64 and 65 and the condensate may be removedfrom said space substantially as fast as it is driven off into suchspace. The apparatus of the invention, therefore, makes it possible todehydrate petroleum products while they are in storage without removalthereof to special apparatus and without special mechanically operatedequipment installed in connection with the tank. The stationarystructure which the invention utilizes having no moving parts andrequiring no motive power makes possible the improvement of the qualityof the petroleum product without the cost of operating such specialequipment.

While the structure embodying the invention has been described in itspreferred forms as particular-ly designed to act both, as acondensationinducing structure and as acondensate-oollect ing structure,it will be understood that the corn densate collecting features of theinvention may be used without taking the specialsteps recommended toinsure that the structure will also act to cool the. vapors coming intocontact with it and thereby cause their condensation. While thestructure will normally be cooled, to a greater or less extent, becauseof the heat conductivity of the connections with the roof and adjacentside wall surfaces of the tank, when the outside atmosphere is coolerthan the ambientatmosphere within the tank, nevertheless, it is a greatadvantage in the storage and handling of petroleum products to insurethe collection and removal of the water condensed on the under side ofthe roof and the adjacent wall surfaces from the air entering the tankin the normal breathing" circulation of air between the atmosphere andthe interior of the tank.

Although the invention has been heretofore described with particularreference to its use in the storing and handling of petroleum andpetroleum products, it will be understood that it has many otherapplications where liquids, either wholly or partially non-miscible withwater, are stored in large tanks normally having constant orintermittent communication with the atmosphere or from which itisdesired to drive off water that has become mixed therewith.

Various modifications of the constructions described, particularly ofthe details for supporting the condensation-inducing and conductingstructure, may be used to suit particular conditions while affording therequisite features of the invention. Therefore, the invention is not tobe deemed as limited, otherwise than as indicated by the appendedclaims.

I claim:

1. In a storage tank for heavy liquids such as petroleum products of lowvolatility having an enclosing wall and a metal roof structureseparating the atmospheric air from the space within the tank, thecombination therewith of a plurality of sheets of heat conductingmaterial of predetermined maximum length supported within said spacebeneath said roof structure with their lengths inclined to thehorizontal and with the lower edge portions thereof in overlapping andvertically spaced relation to the upper edge'portions of the sheetssubjacent thereto to provide a condensation-inducing and conductingstructure extending generally horizontally substantially completelyacross the internal cross section of .said tank, means providing a heatconducting connection from said sheets to the tank structure to maintainsaid sheets at a temperature inducing condensation thereon of watervapor present in said space when condensation of such vapor occurs onsaid roof, the inclination of said sheets being sufficient to cause thewater condensed on the under surface thereof to run on said undersurface toward the lower edges thereof while clinging to said undersurface by surface tension, said sheets providing at their undersurfacethereof a plurality of downwardly projecting rounded ridges each runningin the direction of the inclination of the sheets and spaced aparttransversely of said direction of inclination, said spacing and thelength of the sheets being predetermined in relation to the inclinationof said sheets to provide for accumulating and conducting to said loweredge of each sheet an amount of condensed water which will run upon theundersurface of each ridge and. cling theretoby surface tension withoutdropping therefrom before reaching said lower edge of the sheets andwill drip fromsaid lower edge upon the upper surface of the subjacentsheet, each of said sheetshaving its upper surface formed so as toconduct to its lower edge the water condensed on or falling thereon, andmeans ,for collecting and conducting to a place of disposal the waterdripping from the lower edge of the lowermost sheet.

:2. In a storage tank for heavy liquids such as petroleum products oflow volatility having an enclosing wail and a metal roof structureseparating the atmospheric air from the space within the tank, thecombination therewith of a plurality of sheets of corrugatedshcet metalarranged with their edge portions adjacent each other within said spacebeneath said roof structure to provide a condensation-inducing andconducting structure extending generally horizontally substanti-zlycompletely across the internal cross section of said tank, said sheetsbeing positioned in said condensaticn-inducing and conducting structurewith the lengthwise extent of the corrugations inclined to thehorizontal andwith the lower edges of said sheets transverse to thecorrugations overlapping and spaced vertically above the upper edges ofthe sulojacent sheets, means for supporting said condensationinducingand conducting structure in heat conducting relation to said tankstructure to maintain said sheets at a temperature inducing condensationthereon when condensation occurs on said roof, the size of and spacingbetween the corrugations in each sheet, the inclination of saidsheetsand the maximum lengthwise extent of the corrugations running to thetransverse lower edges thereof being such that water condensed on theunder surface of each of said sheets will collect and run along and uponthe under surface of each downwardly extending corrugation ridge to saidtransverse lower edge and will drip from said edge upon the nextsubjacent overlapped sheet without dropping from Said ridge beforereaching said edge, said vertical spacing of saidoverlapping edges beingsufficient to prevent contact of said water running on said ridge withthe subjacent sheet before reachin said lower edge.

,3. In the combination with a storage tank. according to claim 2 inwhich the roof structure of said tank comprises structural members forsupport thereof extendin radially from a central support toward the tankwall, said sheetsbeing arranged with thecorrugations runningdowm wardlyin the directicn from said central support and generally radially of thesectors formed between each two adjacent radially extending structuralsupporting members, the assembly of said sheets being formed withlateral edges eX- tencling radially and diagonally across thecorrugations to form sectors substantially of the same size and shape asthe sectors between said roof supporting members, and means forsupporting said sector assemblies with said lateral edges thereofclosely adjacent each other, whereby condensation dropping on the sheetsof said assembly is prevented from passing therebetween.

4. In the combination with a storage tank according to claim 2, saidsheets being of rectangular form and arranged in tiers with the adjacenttransverse edges of the tiers in said overlapping vertically spacedrelation and with the corrugations of the sheets of each tier at thelengthwise edges thereof in interfitting overlapping" relation.

5. In the combination with a storage tank according to claim 2, spacersbetween said sheets at said overlapping vertically spaced transverseedges, and means cooperating with said spacers to support both saidsheets in said vertically spaced relation.

6. In the combination with a storage tank according to claim 2, a metalstructural member in heat conducting relation to and extendingtransversely of the corrugations of a superjacent sheet adjacent saidlower transverse edge thereof which overlaps the subjacent sheet andconnected to both of said sheets for support thereof, and a metal hangerproviding a heat conducting connection between said structural memberand said roof structure and supporting said structural member to supportsaid sheets in said condensation-inducing structure.

7. In the combination with a storage tank according to claim 2 in whichthe roof structure of said tank comprises structural members for supportthereof extendin radially from a central support toward the tank wall,said sheets being arranged with the corrugations running downwardly inthe direction from said central support and generally radially of thesector formed between two of said radially extending structuralsupporting members, the assembly of said sheets being formed withlateral edges extending radially and diagonally across the corrugationsto form sectors substantially of the same size and shape as the sectorsbetween said roof supporting members, means for supporting said sectorassemblies with said lateral edges thereof closely adjacent each other,whereby condensation dropping on said assemblies is prevented frompassing therebetween, and a collar extending about said central supportin heat insulating relation thereto for supporting the ends of thesector assemblies adjacent the central support, said sector assembliesbeing arranged in relation to said central support to receive therefromcondensate forming on said central support.

8. In the combination with the storage tank according to claim 2, saidtank being of circular horizontal cross-section, means for collectingand conducting to a place of disposal the water dripping from the loweredge of the lowermost sheet in said condensation-inducing structure,said means comprising a gutter extending generally horizontally alongand conforming substantially to the arc of said tank wall, saidlowermost sheets having the lower edges thereof extending above saidgutter substantially parallel to but spaced from said tank wall, saidmeans for sup porting said condensation-inducing structure ineluding astraight member supported with its ends adjacent said wall andpositioned substantially in the chord of the arc of said wall andsupporting said lowermost sheets with their lower edges in said parallelrelation to said tank wall.

9. In the combination with a storage tank according to claim 2 in whichthe roof structure of said tank comprises structural members for s11port thereof extending radially from a cent support toward the tankwall, said sheets bei g arranged with the corrugations running downwardly in the direction from said central support and generally radiallyof the sector formed between two radially extended supporting members,the assembly of said sheets being formed with lateral edges extendingradially and diagonally across the corrugations to form sectorssubstantially of the same size and shape as the sectors between saidroof supporting members, means for supporting said sector assemblieswith said lateral edges thereof closely adjacent each other, wherebycondensation dropping on said assemblies is prevented from passingtherebetween, said means for supporting said condensation-inducing andconducting structure in- REFERENCES CITED The following references areof record in the file of this patent:

UNITED STATES PATENTS Number Name Date 48,896 Bibby et al. July 25, 1865443,328 McGowan Dec. 23, 1890 885,148 Ellis Apr. 21, 1908 1,076,410Dunham Oct. 21, 1913 1,545,352 Rodriguez July 7, 1925 1,752,197Patterson Mar. 25, 1930 2,229,623 Cooley et al Jan. 21, 1941 2,281,748Carney May 5, 1942 2,353,138 Beach July 11, 1944 2,368,497

Shipley et al Jan. 30, 1945 Certificate of Correction Patent No.2,460,271. February 1, 1949. EDWARD P. BAKER It is hereby certified thaterror appears in the printed specification of the above numbered patentrequiring correction as follows:

Column 13, line 66, claim 1, for the Word their read said;

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Ofiice.

Signed and sealed this 13th day of September, A. D. 1949.

JOE E. DANIELS,

Assistant Uommz'ssimwr of Patents.

